INTRODUCTION TO SOCIOLOGY 667
the west of England, Birmingham, Manchester, Liverpool. In the meantime, as we have seen, the kingdom of Wessex, which occupied exactly the strip of coast facing the continent, was the military center, adapted both to the internal social structure of the British Isles and to the relations with the outside world.
One favorable physical condition, in the midst of all the others which were temporarily unfavorable to the unification of the British Isles, was the climate. These islands are maritime, and hence have a very even and moderate temperature. Ireland, in 50 of latitude, has as high a temperature as the United States at 38 ; that is to say, more than three hundred leagues to the south. It results from this uniformity of temperature that acclimatization in passing either from Scotland to England, or vice versa, was much easier than it was in France for the inhabi- tants of the north and south. 1
Although derived from many diverse races, the present popu- lation of the British Isles has been fused into one in England and in the Scotch Lowlands. At the time of Caesar the mass of the population were Celts, closely related to those of Gaul. In the South, however, there had already been immigrations of Belgae ; that is, of Germanic elements. Later, at the time of the great migrations of the period of the Roman decadence, other tribes, leaving the north of Germany, established themselves in England, massacring or subjugating the earlier inhabitants. The south of England, and not the sea, ought to be regarded as the true fron- tier zone; for it was there that the conflicts and the mingling occurred. Frisians and Saxons occupied particularly the basin of the Thames and the coasts. The Angles, who came from the south of the Cimbric Peninsula, conquered from the Britons the center and the north of England. Later there came to mingle with these, Danes and Northmen from Scandinavia; and later still other Northmen, first transformed by French influence. This was the last violent conquest from without (1066). Later there were still other immigrations, as the result of the religious perse- cutions of the sixteenth and seventeenth centuries, of fugitives from Flanders, from Saintonge, from Cevennes, and from the
1 Elisee Reclus, Geographic universelle.
